Dallas looking at why emergency sirens sounded in error

City officials said a hacker accessed the system and repeatedly sounded the sirens.

"We can't talk a whole lot about the hack itself", said City spokeswoman Sana Syed, "because obviously we don't want this to happen again".

Outdoor emergency warning sirens went off across Dallas late Friday, despite no severe weather or any other live emergency threat. They started sounding around 11 p.m., and the Office of Emergency Management had to turn them off manually.

Locating the hacker, however, "is going to be a very long process if we do find out who actually did it", Vaz said. The city is also working to put in safeguards to avoid these types of hacks again. Vaz said he hoped to have the siren system back up by Sunday.

The sirens sounded off from around 11:42 p.m. Friday night and were shut down at 1:17 a.m. Saturday morning, completing around 15 cycles of a 90-second emergency warning.

Original: That was one way to bring the city together-the 156 sirens that stretch from the border with Lancaster all the way north of 635, ringing for hours for no apparent reason, all of your friends flocking to Twitter for the quips. "We had no malfunction".

The hacker tricked the system to send repeat signals activating each siren 60 times during the night, Vaz said. We won't know the health of our sirens until we reactivate the system. "Making the necessary improvements is imperative for the safety of our citizens", Mayor Rawlings said.